1. Technical Field
This invention relates to a method for bonding a wafer to a substrate using a curable adhesive composition. A method for removing the adhesive is disclosed.
2. Background
As market pressures drive manufacturers toward thinner die packages, one method for reducing the overall height of the package has been thinning of the silicon die. The thinning operation is most efficiently performed on the silicon wafer prior to die singulation. However, as wafers get larger and the dice get thinner, the overall structural integrity of the wafer is reduced. As a result, the large, thin wafers may break when processed using existing equipment and materials.
One proposed solution to this problem is to adhesively bind the wafer to a reinforcing substrate (such as another wafer or a wafer carrier) to increase mechanical strength, perform the desired processing, e.g., thinning, and release the wafer before singulation. The adhesive and substrate in this process act as a mechanical support to provide the structural stability during processing.
There is a need in the semiconductor industry for a temporary wafer bonding process using an adhesive having properties to allow for processing the wafer. The adhesive should be capable of being applied by an industrially acceptable method (such as spray coating, printing, dipping, or spin coating), should be capable of withstanding processing at temperatures above 200° C. for several hours, should be robust to various commonly used electronic chemicals, and should release cleanly from the wafer on command.